Screw-cutting implement



(No Model.)

B. BOWMAN. SCREW GUTTING IMPLEMENT.

. N0. 4 9,092. Patented June 6,1893.

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UNITED STATES PATENT OFFICE.

REUBEN BOWMAN, OF MIDDLETOWN, PENNSYLVANIA.

SCREW-CUTTING IMPLEMENT.

SPECIFICATION forming part of Letters Patent No. 499,092, dated June 6,1893.

Application filed January 31, 1893. $erial No. 460.325. (No model.)

To all whom it may concern:

Be it known that I, REUBEN BOWMAN, a citizen of the United States, and aresidentof Middletown, in the county of Dauphin and State ofPennsylvania, have invented certain new and useful Improvements inScrew-Outting Implements; and I do hereby declare that the following isa full, clear, and exact description of the invention, which will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, which form apart of this specification.

My invention relates to improvements in devices for screw-threadingtaps, bolts, and other similar articles, but is more especially intendedfor threading taps for cutting threads in pipe couplings or sockets.

The object of the invention is to providea novel construction of diestock and dies, which shall possess superior advantages with respect toutility and efficiency.

The invention consists in the novel construction and combination ofparts hereinafter fully described and claimed.

In the accompanying drawings: Figure 1 is a central vertical sectionalview of a screw cutting instrument constructed in accordance with myinvention. Fig. 2 is a horizontal section, on the line oc0c, Fig. 1.Fig. 3 is a similar section, on the line y-y, Fig. 1. Figs. at and 5 areperspective views of the dies removed from the stock. Fig. 6 is a viewof a tap threaded by my improved-device.

In the said drawings, the reference numeral 1 designates the die stockconsisting of a metal cube or block having a rectangular apertureextending therethrough. This block is provided with heads 2 at each endsecured thereto by screw-bolts or other fastening devices, and each isprovided with a circular aperture 3, aligned witb,but of less area thancheaperture in the block.

The reference numeral 4 designates a series of superimposed cuttingdies, located in the aperture in the block 1, and confined in place bymeans of the heads 2. Each of these superimposed dies consists of twoplates or. sections of equal area or size, having theirinner facesformed with spaces 5, and cutting threads or teeth in a semi-circularline, as is usual in this class of devices.

Passing through apertures in the blocks at right angles to andcommunicating with the rectangular aperture, are a number of set screws6,the inner ends of which bear against one of the edges of each set ofdies, by means of which the dies may be adjusted to compensate for anyslight variations in the cutting edges or threads, which are liable tooccur from continued use. These dies are so arranged with respect toeach other, that the cutting threads of one set will alternate with thespaces in the next adjoining set, preventing rounding of the front edgeof the tap, which is liable to occur, when what is known as sectionaltaps are being cut, that is, taps having a series of grooves 7in betweenthem,'

as seen in Fig. 6, which represents a tap cut with an instrumentconstructed in accordance with my invention. The meeting edges of eachset of dies is formed at an angle to the.

edges of the adjoining dies, so as to break joints.

The operation will be readily understood: The tap blank to be threadedis inserted between the dies, and then rotated by any suitable means,and by once passing through the series of superimposed dies, the threadsare cut thereon, and the tap is then ready for tempering.

Having thus described my invention, What I claim is- In a screw-cuttinginstrument, the combination with the stock having a rectangular aperturetherein, the heads secured thereto having circular apertures, and theset screws passing through apertures in the stock at right angles to therectangular aperture and communicating therewith, of the superimposedsets of dies, each set consisting of two plates, the meeting edges ofwhich are at an angle with the adjoining sets, so as to break joints,and each plate or die formed with a series of cutting threads andspaces, alternating the teeth and spaces of the adjoining dies,substantially as described. I

In testimony that I claim the foregoing as my own I have hereuntoaflixed my signature in presence of two witnesses.

REUBEN BOWMAN. IVitnesses:

H. B. LAUMAN, J. W. PATTON.

